Work vehicles such as agricultural tractors or construction vehicles are often equipped with auxiliary hydraulic systems for supplying hydraulic fluid from the vehicle hydraulic pump to equipment or attachments coupled to the work vehicle. For example, U.S. Pat. No. 5,887,669 discloses such an auxiliary hydraulic control system including a number (e.g., 5) of proportional valves for controlling the hydraulic fluid flow to an equal number of attachments. Each of the proportional valves is capable of supplying fluid to an attachment at a "feathered" flow rate (e.g., proportional control) as commanded by the vehicle operator using a valve control lever. Each of the valves can also be operated as an ON/OFF valve to turn on or turn off the hydraulic fluid flow. The '669 patent is commonly assigned with the present application, and is incorporated by reference herein in its entirety.
When an auxiliary hydraulic system as in the '669 patent is coupled to an hydraulically-powered implement such as a scraper equipped with hydraulic cylinders for raising and lowering a scraper blade, the operator often must manually actuate the command devices for the auxiliary hydraulic system, such as the auxiliary valve control lever, to control the operation of the scraper. Where more than one scraper is involved, the operator must simultaneously manipulate multiple control levers. This manual operation requires a high level of skill, can produce inaccurate results even with a skilled operator, causes a relatively high degree of wear and tear on the hydraulic system, and can be relatively unproductive.
Some implements driven by on-board hydraulic actuators such as hydraulic cylinders or motors have on-board proportional valves which provide a proportional fluid flow to the actuators under control of an implement controller. For example, scrapers can include a scraper body having an earth-contacting blade attached thereto, on-board hydraulic actuators (cylinders) for raising and lowering the scraper body to change the vertical location of the blade with respect to the ground, proportional valves for providing a flow of hydraulic fluid to the actuators, a laser for sensing the contours of the land over which the scraper travels, and a controller for reading the laser data and for determining control signals based on the laser data and operator-entered grade and elevation data which are then applied to the proportional valves to raise and lower the blade. When such a scraper is pulled by a work vehicle equipped with an auxiliary hydraulic system capable of supplying proportional flows, the valves in both the vehicle and scraper become redundant.
Accordingly, it would be desirable to provide an automatic control system for an hydraulically-powered implement coupled to an auxiliary hydraulic system of a work vehicle to provide better control of the implement, simplified use, easier setup, less wear and tear on the auxiliary hydraulic system of the vehicle, improved productivity and lower total system cost to the customer. It would also be desirable to provide an auxiliary hydraulic system wherein a remote valve can be automatically and remotely controlled in response to a signal from the implement. It would be desirable to provide an auxiliary hydraulic system wherein multiple auxiliary valves are automatically and remotely controlled by multiple implements coupled to the vehicle. The implement(s) would use ("borrow") the valve(s) which are already part of the vehicle's auxiliary hydraulic system, and the implement itself would not need to be equipped with these valves, significantly decreasing costs.
It would further be desirable to provide a switch on a control console mounted in the vehicle cab which would allow the operator to enable and disable the automatic and remote control by the implement. It would be desirable to provide such an auxiliary hydraulic control system configured to ignore the external signal provided by the implement in the event that the operator moves the auxiliary control lever located in the cab, thereby giving the operator the capability of overriding the automatic and remote auxiliary control. Further, it would be desirable to provide such an auxiliary hydraulic control system configured to ignore the external control signals provided by the implement whenever the vehicle is stationary. In addition, whenever the implement is providing the control signals for the auxiliary hydraulic system of the vehicle (i.e., as opposed to when the cab-mounted auxiliary control levers provide the control signals), it would be desirable to provide a cab-mounted display which provides visible indicia (e.g., "AUTO") to the vehicle operator to inform the operator that the automatic and remote auxiliary control is activated.